The present invention relates to antigen-binding molecules, preferably antibodies or antigen-binding fragments thereof, that specifically bind to a GP73, or to an antigenic portion thereof, wherein the antigen-binding molecule binds to an epitope within the extracellular part of GP73 that is internalized into a cell usually subsequent to proteolytic cleavage. The invention further relates to immunoconjugates comprising the antigen-binding molecules, in particular the anti-GP73 antibodies, or antigen-binding fragments thereof. The antigen-binding molecules and immunoconjugates of the invention may be administered alone, as a therapeutic conjugate or in combination with other naked antibodies, or with therapeutic agents, or with other immunoconjugates or as a diagnostic conjugate. The present invention also relates to nucleotide sequences encoding anti GP73 antibodies, and immunoconjugates, vectors and host cells containing the nucleotide sequences, and methods of making anti-GP73-antibodies. The antigen-binding molecules, antibodies and compositions of the invention are useful in diagnostic and therapeutic applications for diseases in which expression of GP73 is altered, in particular in which GP73 is overexpressed, such as cancer.